Preheat grill to medium. Brush tenderloins with olive oil and grill 10 to 12 minutes, turning every 2 to 3 minutes.
Allow turkey to cool. Cut into 1/2-inch cubes. In medium bowl, combine turkey with walnuts, grapes, celery, carrot, onion and dressing and toss lightly. Line serving dish with lettuce leaves and arrange salad on top.
Turkey recipes courtesy of grilling guru George Hirsch and Shady Brook Farms, Dayton, VA